Composite structures are typically constructed from multiple layers or plies. The plies, in turn, are generally made up of a series of courses that slightly overlap or abut one another. These courses may include a variety of materials such as glass, aramid, and carbon fiber, various other fibers, and the like. In addition, the fibers may be oriented in a single direction or woven into a fabric. The course material may further be pre-impregnated with a resin and are often dispensed from a roll. In roll form, the course material typically includes a separator film or backing film of plastic, paper, or the like. This backing film generally prevents resin coated or pre-impregnated course material (prepreg) from adhering to itself.
The courses are generally laid upon the form or tool along a “natural path” of the course material. The term “natural path” refers to the path the course material would follow when rolled out on to the surface of the tool. Deviations from the natural path are generally achieved by applying force across the width of the course material. When the force applied exceeds the flexing capacity of the material, wrinkles or bridges form in the course material. In addition, the wider the course is, the more prone the course material is to wrinkle. However, in general, it is advantageous to utilize relatively wide course material so as to increase layup rates. Conventional methods of constructing contoured composite structures from fabric course material employ skilled technicians to hand lay the fabric. These technicians pull on the edges and corners of the fabric to deform or trellis the weave of the fabric. In this manner, the fabric is induced to conform to the contour.
When laying a course adjacent to a previously applied course the natural path of the course across a contour may cause the courses to diverge or converge. In order to prevent gaps or excessive overlap, the side edge or profile of the course is trimmed to maintain an appropriate relationship. Conventional methods of trimming or profiling also generally employ skilled technicians to perform these tasks. As a result, hand layups of contoured surfaces with fabric course material is expensive and time consuming.
Accordingly, it is desirable to provide a system for generating composite items that is capable of overcoming the disadvantages described herein at least to some extent.